The purpose of the proposed project is to determine how changes of diet influence carbohydrate metabolism in rats. Effects of carbohydrate restriction, high fat feeding, starvation, altered feeding patterns and obesity on hepatic gluconeogenesis are to be investigated. The mechanisms by which dietary alterations lead to enhanced gluconeogenesis will be elucidated by studies of insulin and glucagon secretion, of liver cyclic AMP concentration and of the reactions which regulate gluconeogenesis. Glucose utilization in rats on carbohydrate-restricted diets will be evaluated to learn whether animals adapt to such a regimen by reducing utilization of carbohydrate and increasing use of other nutrients as fuel.